title: [Recognition and cleavage of apurinic sites in DNA by the tripeptide lysyl-tryptophyl-lysine].
abstract: Tryptophan-containing peptides, such as Lys-Trp-Lys, Lys-Trp-Gly-Lys and Lys-Gly-Trp-Lys, bind with high affinity to apurinic sites in DNA. The association constant for binding of Lys-Trp-Lys to an apurinic site is two orders of magnitude higher than that for binding to a native site. This is due to a very efficient stacking of tryptophan with the bases on both sides of the vacant apurinic site. When the complexes were incubated at 37 or 45 degrees C a cleavage of the phosphodiester bond was observed. Using pBR 322 DNA containing apurinic sites, conversion of the superhelical to the relaxed circular form was observed as a result of single-strand breakage. The peptide Lys-Gly-Lys had no effect and Lys-Trp-Lys did not induce any cleavage in pBR 322 DNA which did not contain any apurinic site. Therefore, a simple tripeptide, Lys-Trp-Lys, exhibits both the specificity of recognition and the activity of an endonuclease for apurinic sites in DNA.
mesh_terms: D001080:Apurinic Acid / Q000378:metabolism*; D001665:Binding Sites; D004247:DNA / Q000378:metabolism*; D004278:DNA, Superhelical / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology*; D010957:Plasmids; D011119:Polynucleotides / Q000378:metabolism*
chemical_list: D004278:DNA, Superhelical; D009842:Oligopeptides; D011119:Polynucleotides; D001080:Apurinic Acid; C029535:lysyl-tryptophyl-alpha-lysine; D004247:DNA
vernacular_title: Reconnaissance et coupure des sites apuriniques dans l'ADN par le tripeptide lysyl-triptophyl-lysine.